This is an excellent question.
Ram is the last manufacturer to offer it, however, the take-rate from my own experience is incredibly low due to how de-rated the manual offering is -
68RFE Auto - 370 HP - 800 lb/ft
Manual - 350 - 660
AISIN - 385 -925
It's a tough pill to swallow for some clients, losing over 200 lb/ft of torque potentially.
Your average consumer will not ever use their peak torque. They are paying extra money for the HO engine for no reason. (Which is obviously fine with FCA).
The commercial models, which are more likely to run at peak torque, are only rated for 750 lb-ft with the Aisin. International or Freightliner will sell you a truck with the same Cummins 6.7 engine, and it will be rated the same at 750 lb-ft, even with a manual transmission. So FCA
could have offered a manual without de-rating the torque/towing/GVWR.
Of course this has nothing to do with the question. Will there be a manual available on the new model? We are halfway through 2018 right now, the Ram HD is one of the biggest products for FCA, they must have already decided what options will be available.
